Although new concepts for complex vertical carbon nanotube devices have been proposed in recent years, the means to establish individual electrical contacts and structural support to vertical SWNTs have not been demonstrated. In part, the inability to synthesize vertical SWNTs in predefined locations has hindered advancement of the topic. Various embodiments of the invention include both a robust process to synthesize SWNTs reproducibly in vertical, long-range ordered channels suitable for device integration and a facile means to contact the top and bottom of SWNTs simultaneously without the use of any lithographic procedures. Additionally, the process allows individual SWNTs to be annularly contacted in situ from their points of origin by metallic nanowires for establishment of electrical contact.
SWNTs have been integrated into numerous electronic and chemical sensing devices to exploit their exceptional electronic transport properties and potential for high-density integration. Current device contact metallization procedures include the direct deposition of lithographically defined metallic contact pads onto a substrate containing SWNTs or the dispersion of SWNTs onto pre-defined contact pads. These procedures generally exhibit low yields and are limited to two-dimensional, planar architectures. Although horizontal structures have proven invaluable for examination of SWNT transport properties and functional material selection, their flexibility is limited and precludes the exploitation of the nanometer-scale diameter of SWNTs as a scaling metric for device integration. A vertical SWNT device would allow for increased integration density and a wrap-around gate geometry, providing excellent control over the channel electrostatics. However, the inability to support and electrically address vertical nanotubes has prevented vertical devices from being realized.